Rotor



Oct; 7, 1941.

T. TQGNOLA Filed Dec. 3, 1958 F, INVENTOR. w&0

TORNEY' .netic rotors low speed nor a Patented Oct. 7, 1 941 ao'ron' Tullio Tognola, Aviation C Sidney, N. 1., orporation, South poration of Delaware Application December 1 Claim.

This invention relates to electrical apparatus and more particularly to rotors adapted for use in magneto generators and the like.

Rotors for magneto generators and like electrical apparatus are rotated at high speed for long periods of time and the parts thereof are accordingly subjected to large and persistent centrifugal forces. As a result of this fact, known rotors of the above character have been constructed from relatively heavy and expensive castings which require considerable machining before assembly. Prior rotors have also been made up of a comparatively large number of such parts and have accordingly been expensive to manufacture and assemble. Rotors that are so constructed are heavy, thereby requiring relatively large amounts of energy for rotation thereof, and also bulky, thereby requiring a relatively large housing space for a given output capacity. From the electrical point of view, magheretofore provided have not been entirely satisfactory in that the same have not been able to produce a large enough current at sufficiently constant current over a broad range of speeds beginning with a relatively low speed. c

It is accordingly one of the objects of the present invention to provide a novel magnetic rotor which is adapted for use in a magneto generator to render the same capable of generating a substantially constant maximum current over a wide range of speeds.

Another object is to'provide a novel magnetic rotor which is so constructed as to have a high coercive force and, hence, to produce relatively high current at lowspeeds when employed as part of a magneto generator A further object is a novelly constructed magnetic rotor which is mechanically simple, strong and durable and electrically efficient.

Still another object is to provide a novel multieto rotor which comprises only ba e polar magn small number of simple parts which may readily and inexpensively manufactured and as-- semb (1 A still. further object is to provide a novel magnetic rotor which is smaller and lighter than prior rotors of like capacity.

,The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the animalto Bendix Bend, Ind., a cor- 1938, Serial No. 243,701

purpose of illustration only and is not intended as a definition of the limits of the invention, reference for this latter purpose being had primarilyto the appended claim.

In the drawing wherein like reference characters; refer to like parts throughout the several views,

Fig. 1 is a side elevation, partly in section, of one form of two-pole magnetic rotor embodying the present invention;

Fig. 2 is a transverse section taken substantially on line 2-4 of Fig. 1; and,

Fig. 3 is a similar sectional view of a fourpole rotor embodying the invention.

One form of rotor embodying the present invention is illustrated in Figs. 1 and 2, of example, as a two-pole rotor adapted for use in a magneto generator and comprising a simple cylindrical shaft 5 which may be rotatably jourmanner in a suitable generator housing. If desired, a cooling fan 6 may be secured to the central portion of shaft 5.

In order to facilitate assembly, minimize the cost and number of necessary parts, and reduce the weigh thereof and space occupied thereby,

without afiecting the emciency and durability rotor is constructed in the form of a novel unit comprising a permanent magnet 1 which is .pref erably cylindrical with magnetic poles of oppositepolarity alternately arranged around the periphery thereof in a known manner. Surrounding magnet I and contacting the entire outer surface thereof are a plurality of annular laminations 3 of comparatively soft, flux-conducting metal which are constructed in a novel manner to hereinafter appear. Laminations 8 and magnet 1 are held together as apart of a unitary structure and centered with respect to shaft 5 by a pair of novel retaining plates 9 engaging the ends of the magnet and a plurality of bolts or rivets Ill extending longitudinally of shaft 5 through said end plates and laminations.

In the form illustrated, novel end plates 9 are constituted by non-magnetic sheet-metal stampings which are of light weight and yet strong and which may be rapidly and inexpensively manufactured. Each of said end plates has an integral axially extending hub portion H formed at the center thereof for close sliding engagement with shaft 5 and a plurality of openings for receiving rivets l0. Magnet a bore the latter by end plates by way 'therethrough 9 and laminations 8. The rigid magnetic unit thus provided may be readily assembled, slipped into position 5 and secured against rocurrent over a wide laminations 8 is stamped out from flux-conducting sheet metal in respectively, circumferentially thereof, a thick portion l5 beof the mag- The residual thus higher or like mafrom the magnetizing machine. magnetism of the present rotor is than it is in rotors heretofore made terials and the current generated neto embodying the present rotor will accordingly reach a maximum or nearly maximum at a slower speed of rotation of the rotor.

Additionally, of bars 16, the

radial direction a nickel-aluminum-iron alloy magnet or approximately one vention having an outside diameter by a magand three-quarters inches was employed with laminated sort-iron pole shoes of the character illustrated, the

are formed with twice as many equally-spaced thick and thin portions l5 and tion of the four-pole rotor is the same as above described except the magneto coil occur for each revolution of the rotor.

tofore known.

What is claimed is. h magnetic rotor comprising a shaft, drical magnet surrounding said shaft, said mag- I'ULLIO TOGN OLA. 

